Technical Field
[0001] The present invention relates to continuous ink jet printers and, more particularly,
to improved construction for the orifice plate.
Background Art
[0002] Ink jet printing systems are known in which a print head defines one or more rows
of orifices which receive an electrically conductive recording fluid, such as for
instance a water base ink, from a pressurized fluid supply manifold and eject the
fluid in rows of parallel streams. Printers using such print heads accomplish graphic
reproduction by selectively charging and deflecting the drops in each of the streams
and depositing at least some of the drops on a print receiving medium, while others
of the drops strike a drop catcher device.
[0003] In one type of ink jet printer, the print head includes a manifold, defining a fluid
receiving reservoir, to which is bonded a relatively thin orifice plate, defining
the rows of orifices. The orifice plate is made of electroplated nickel or beryllium-copper
electroplated with nickel. The orifice plate is somewhat flexible.
[0004] Currently in the art, an orifice plate is bonded to a holder, such as a droplet generator
body, by first electroplating the orifice plate on a mandrel and then removing the
orifice plate from the mandrel. The orifice plate is then typically bonded onto the
orifice plate holder by using an epoxy. Of course, it is also possible, by using the
right kind of mandrel, to epoxy bond the orifice plate to a holder or droplet generator
while the orifice plate is still on the mandrel.
[0005] Unfortunately, several problems exist with prior art orifice plate fabrication techniques.
One, debris is introduced from the technique of applying the epoxy fillet. Second,
the epoxy bond diminishes efficiency of acoustic energy transfer. The epoxy thickness
variation and the variation in the distance the epoxy is from the orifices along the
array will cause variations in the amount of acoustic energy transferred to the filaments
and hence variations in the breakoff length of the filaments along the array. Also,
handling of the delicate orifice foil of the current art introduces out-of-flatness
in the plane of the orifice plate and a non-straightness of the orifices along the
orifice array.
[0006] It is seen then that there exists a need for an improved orifice plate fabrication
which overcomes the problems associated with the prior art.
Summary of the Invention
[0007] In accordance with the present invention, a method of fabricating an orifice plate
for an ink jet printer comprising the steps of:
providing a mandrel having a peg thereon;
aligning a holder to the mandrel;
placing the mandrel and the holder at cathodic polarity;
applying an electroplating metal to the mandrel and the holder so as to grow the electroplated
metal on the mandrel around the peg to cause the mandrel and the holder to form a
single orifice plate directly bonded to the holder.
[0008] The direct orifice plate plating method according to the present invention, wherein
the orifice plate is bonded directly from the mandrel onto the holder, by means of
plating seeks to meet the above-mentioned need.
[0009] The present invention provides an orifice plate wherein the plate is bonded directly
from the mandrel onto a holder or droplet generator. This provides the advantage of
eliminating the use of epoxy on the flexible orifice plate. Acoustic energy will be
transferred more uniformly through a stiffer orifice plate holder/epoxy/ fluid manifold
structure than the orifice plate/epoxy/fluid manifold structure. The epoxy can be
eliminated if the orifice plate is directly plated to the fluid manifold. The present
invention provides such an orifice plate wherein the bonding is accomplished by means
of plating. This provides the advantage of allowing for the orifice plate to be a
mechanically stiffer structure. Being a mechanically stiffer structure will greatly
reduce the out-of-flatness in the plane of the array and the non-straightness of the
orifices along the array. Also the mechanically stiffer structure will transfer acoustic
energy more uniformly along the array which will improve the uniformity of the breakoff
lengths of the filaments along the array.
[0010] The peg is desirably a photoresist peg.
Brief Description of the Drawings
[0011]
Fig. 1 is a prior art cross sectional view of an orifice plate bonded to a fluid manifold;
Fig. 2 is a cross sectional view of an orifice plate holder in close proximity to
a mandrel, in accordance with the present invention;
Fig. 3 is a cross sectional view of the orifice plate holder and mandrel of Fig. 2
electroplated with nickel, in accordance with the present invention;
Fig. 4 is a cross sectional view of an integrated orifice plate holder and orifice
plate, in accordance with the present invention; and
Fig. 5 is a cross sectional view of an orifice plate directly plated onto a fluid
manifold, in accordance with the present invention.
Detailed Description of the Preferred Embodiments
[0012] Currently in the art, the orifice plate is made by electroplating metal onto a mandrel.
A mandrel can be defined as a form which when electroplated gives a metal part with
the desired features. The features are formed by having areas on the mandrel which
do not electroplate. This is accomplished by having areas on the mandrel which are
made of a dielectric material. The dielectric material can be material put on top
of a conductive material such as photoresist. Another method of mandrel construction
is to coat a dielectric material with a conductive surface. The dielectric areas are
then obtained by etching through the conductive surface down to the dielectric, such
as are described in U.S. Patent No. 4,773,971; and European patent application No.
95307490.3 (EP-A-0713929)
[0013] Either style of mandrel can be used to directly plate orifice plates onto a holder,
in accordance with the present invention. The type of mandrel with a dielectric on
a conductive surface shall be used to demonstrate the method of directly plating an
orifice plate onto a holder. The mandrel is then placed into a metal electroplating
bath, e.g. nickel or nickel alloy. Metal is then electroplated onto the mandrel where
only areas devoid of the dielectric material accept the electroplated nickel. The
orifice plate can then be removed from the mandrel. This process is described in U.S.
Pat. No. 4,184,925.
[0014] Referring now to Fig. 1, orifice plate 10 is bonded to manifold 12, with suitable
bonding means such as epoxy 14, at the periphery of the orifice plate. This bridges
and closes the manifold opening leading to fluid reservoir 16. As a consequence, orifices
in the orifice plate 10 are in direct fluid communication with the reservoir 16. As
fluid is applied under pressure to the fluid receiving reservoir, it flows through
fluid channel 18, to orifices of the orifice plate 10, and emerges from each orifice
as a fluid filament. The fluid filament then breaks at its tip into a succession of
fluid drops. The length of the filament can be controlled by the amount of stimulation
amplitude applied to the filament from piezoelectric crystals 20 attached to the fluid
manifold 12. It is desirable to have all the filament lengths along the array to be
the same. This is called synchronous breakoff.
[0015] In accordance with one embodiment of the present invention, a method of bonding an
orifice plate onto a holder for an ink jet printer uses direct plating. Referring
now to Fig. 2, initially an orifice plate holder 22 is aligned to a mandrel 24 and
the two parts are kept in very close proximity, preferably in intimate contact, and
at the same electrical potential. The holder and the mandrel are then placed at cathodic
polarity. The orifice is formed as the electroplated metal grows on the conductive
portion of the mandrel and around a photoresist peg 26. If necessary, metal can be
deposited thick enough to go over part of the top of the peg.
[0016] Continuing with Fig. 2 and referring to Fig. 3, plating material, such as electroplated
nickel 28, is applied to the combined holder and mandrel. The holder 22 and the mandrel
24 will then grow together, forming a single orifice plate directly bonded to the
holder. The mandrel can then be removed by peeling, if the adhesion of the plated
material is less on the mandrel than the holder, or by etching the mandrel away, as
is illustrated in Fig. 4.
[0017] Referring now to Fig. 5, there is illustrated a cross sectional view of an orifice
plate 30 manufactured in accordance with the present invention, directly plated onto
fluid manifold 12. In comparing Fig. 5 of the present invention with Fig. 1 of the
prior art, the differences between the present invention and the prior art are quite
clear. Specifically, the epoxy 14 layer of the prior art has been eliminated with
the present invention. In Fig. 5, an anode may be axially located at location 32,
down the interior of the fluid manifold cavity. An electrolyte is pumped through the
fluid manifold cavity during the plating process to assure that the concentration
of metal ions being plated is uniform throughout the length of the fluid manifold
cavity. If the concentration of metal ions is not uniform, then the orifice plate
will not be uniform in thickness along the array, resulting in a variation in the
diameter of the orifices along the array.
Industrial Applicability and Advantages
[0018] The present invention is useful in the field of ink jet printing, and has the advantage
of eliminating the use of epoxy on the flexible orifice plate. Acoustic energy will
be transferred more uniformly through a stiffer orifice plate holder/epoxy/fluid manifold
structure than the orifice plate/epoxy/fluid manifold structure. It is a further advantage
of the present invention that it allows for the orifice plate to be a mechanically
stiffer structure. Being a mechanically stiffer structure will greatly reduce the
out-of-flatness in the plane of the array and the nonstraightness of the orifices
along the array. Also the mechanically stiffer structure will transfer acoustic energy
more uniformly along the array which will improve the uniformity of the breakoff lengths
of the filaments along the array.
[0019] Having described the invention in detail and by reference to the preferred embodiment
thereof, it will be apparent that other modifications and variations are possible
without departing from the scope of the invention defined in the appended claims.
1. A method of fabricating an orifice plate for an ink jet printer comprising the steps
of:
providing a mandrel (24) having a peg (26) thereon;
aligning a holder (22) to the mandrel (24);
placing the mandrel (24) and the holder (22) at cathodic polarity;
applying an electroplating metal to the mandrel (24) and the holder (22) so as to
grow the electroplated metal on the mandrel (24) around the peg (26) to cause the
mandrel and the holder to form a single orifice plate directly bonded to the holder.
2. A method of fabricating an orifice plate as claimed in claim 1 further comprising
the step of maintaining the mandrel (24) and the holder (22) in intimate contact.
3. A method of fabricating an orifice plate as claimed in claim 1 further comprising
the step of maintaining the mandrel (24) and the holder at equal electrical potential.
4. A method of fabricating an orifice plate as claimed in claim 1 further comprising
the step of removing the mandrel (24) from the orifice plate (28).
5. A method of fabricating an orifice plate as claimed in claim 4 wherein the step of
removing the mandrel (24) from the orifice plate (28) comprises the step of peeling
the mandrel (24) from the orifice plate (28).
6. A method of fabricating an orifice plate as claimed in claim 4 wherein the step of
removing the mandrel (24) from the orifice plate (28) comprises the step of etching
the mandrel (24) off the orifice plate (28).
7. A method for fabricating an orifice plate as claimed in claim 1 wherein the peg is
a photoresist peg
1. Verfahren zum Herstellen einer Öffnungsplatte für einen Tintenstrahldrucker, welches
folgende Schritte umfaßt:
Bereitstellen eines mit einem Zapfen (26) versehenen Formkerns (24),
Ausrichten eines Trägers (22) nach dem Formkern (24),
Anordnen des Formkerns (24) und des Trägers (22) an einer Kathodenpolarität.
Aufgalvanisieren von Metall auf den Formkern (24) und den Träger (22), um galvanisch
abgeschiedenes Metall auf dem Formkern (24) um den Zapfen (26) herum aufbauen zu lassen,
damit Formkern und Träger eine einstückige, unmittelbar mit dem Träger verbundene
Öffnungsplatte bilden.
2. Verfahren zum Herstellen einer Öffnungsplatte nach Anspruch 1, weiter enthaltend einen
Schritt, bei dem der enge Kontakt zwischen Formkern (24) und Träger (22) beibehalten
wird.
3. Verfahren zum Herstellen einer Öffnungsplatte nach Anspruch 1, weiterhin enthaltend
einen Schritt, bei dem der Formkern (24) und der Träger auf dem selben elektrischen
Potential gehalten werden.
4. Verfahren zum Herstellen einer Öffnungsplatte nach Anspruch 1, weiterhin enthaltend
den Schritt der Abnahme des Formkerns (24) von der Öffnungsplatte (28).
5. Verfahren zum Herstellen einer öffnungsplatte nach Anspruch 4, bei dem der Schritt
der Abnahme des Formkerns (24) von der Öffnungsplatte (28) den Schritt des Abziehens
des Formkerns (24) von der Öffnungsplatte (28) beinhaltet.
6. Verfahren zum Herstellen einer Öffnungsplatte nach Anspruch 4, bei dem der Schritt
der Abnahme des Formkerns (24) von der Öffnungsplatte (28) den Schritt des Abätzens
des Formkerns (24) von der Öffnungsplatte (28) beinhaltet.
7. Verfahren zum Herstellen einer Öffnungsplatte nach Anspruch 1, bei dem der Zapfen
ein Photoresistzapfen ist.
1. Procédé de fabrication d'une plaque à orifice pour une imprimante à jet d'encre, comprenant
les étapes suivantes :
- la prévision d'un mandrin (24) possédant une cheville (26) montée dessus ;
- l'alignement d'un support (22) sur le mandrin (24) ;
- le placement du mandrin (24) et du support (22) sur une polarité de cathode ;
- l'application d'un métal de galvanoplastie sur le mandrin (24) et le support (22)
de façon à développer le métal de galvanoplastie sur le mandrin (24) autour de la
cheville (26) pour amener le mandrin et le support à former une plaque à un seul orifice
directement liée au support.
2. Procédé de fabrication d'une plaque à orifice selon la revendication 1, comprenant,
de plus, une étape de maintien du mandrin (24) et du support (22) en contact intime.
3. Procédé de fabrication d'une plaque à orifice selon la revendication 1, comprenant,
de plus, une étape de maintien du mandrin (24) et du support (22) à un potentiel électrique
égal.
4. Procédé de fabrication d'une plaque à orifice selon la revendication 1, comprenant,
de plus, une étape d'enlèvement du mandrin (24) de la plaque d'orifice (28).
5. Procédé de fabrication d'une plaque à orifice selon la revendication 4, selon lequel
l'étape d'enlèvement du mandrin (24) de la plaque d'orifice (28) comprend une étape
de pelage du mandrin (24) de la plaque d'orifice (28).
6. Procédé de fabrication d'une plaque à orifice selon la revendication 4, selon lequel
l'étape d'enlèvement du mandrin (24) de la plaque d'orifice (28) comprend une étape
de gravure chimique du mandrin (24) de la plaque d'orifice (28).
7. Procédé de fabrication d'une plaque à orifice selon la revendication 1, selon lequel
la cheville est une cheville photorésistante.